A few months ago I asked Valve for permission to publish my Half-Life fan game on Steam and... guess what? Codename: Loop is coming to Steam, hopefully with a demo later this year!
The game will be completely free.
#CodenameLoop
The latest Codename: Loop demo build is available in ModDB!
This is a demo build featuring a small section of Questionable Ethics (adapted by Hezus) and custom maps support.
More info in the link.